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1.
J Biol Chem ; 300(6): 107368, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38750793

RESUMO

Activating signal co-integrator complex 1 (ASCC1) acts with ASCC-ALKBH3 complex in alkylation damage responses. ASCC1 uniquely combines two evolutionarily ancient domains: nucleotide-binding K-Homology (KH) (associated with regulating splicing, transcriptional, and translation) and two-histidine phosphodiesterase (PDE; associated with hydrolysis of cyclic nucleotide phosphate bonds). Germline mutations link loss of ASCC1 function to spinal muscular atrophy with congenital bone fractures 2 (SMABF2). Herein analysis of The Cancer Genome Atlas (TCGA) suggests ASCC1 RNA overexpression in certain tumors correlates with poor survival, Signatures 29 and 3 mutations, and genetic instability markers. We determined crystal structures of Alvinella pompejana (Ap) ASCC1 and Human (Hs) PDE domain revealing high-resolution details and features conserved over 500 million years of evolution. Extending our understanding of the KH domain Gly-X-X-Gly sequence motif, we define a novel structural Helix-Clasp-Helix (HCH) nucleotide binding motif and show ASCC1 sequence-specific binding to CGCG-containing RNA. The V-shaped PDE nucleotide binding channel has two His-Φ-Ser/Thr-Φ (HXT) motifs (Φ being hydrophobic) positioned to initiate cyclic phosphate bond hydrolysis. A conserved atypical active-site histidine torsion angle implies a novel PDE substrate. Flexible active site loop and arginine-rich domain linker appear regulatory. Small-angle X-ray scattering (SAXS) revealed aligned KH-PDE RNA binding sites with limited flexibility in solution. Quantitative evolutionary bioinformatic analyses of disease and cancer-associated mutations support implied functional roles for RNA binding, phosphodiesterase activity, and regulation. Collective results inform ASCC1's roles in transactivation and alkylation damage responses, its targeting by structure-based inhibitors, and how ASCC1 mutations may impact inherited disease and cancer.

2.
Am J Hum Genet ; 111(3): 487-508, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38325380

RESUMO

Pathogenic variants in multiple genes on the X chromosome have been implicated in syndromic and non-syndromic intellectual disability disorders. ZFX on Xp22.11 encodes a transcription factor that has been linked to diverse processes including oncogenesis and development, but germline variants have not been characterized in association with disease. Here, we present clinical and molecular characterization of 18 individuals with germline ZFX variants. Exome or genome sequencing revealed 11 variants in 18 subjects (14 males and 4 females) from 16 unrelated families. Four missense variants were identified in 11 subjects, with seven truncation variants in the remaining individuals. Clinical findings included developmental delay/intellectual disability, behavioral abnormalities, hypotonia, and congenital anomalies. Overlapping and recurrent facial features were identified in all subjects, including thickening and medial broadening of eyebrows, variations in the shape of the face, external eye abnormalities, smooth and/or long philtrum, and ear abnormalities. Hyperparathyroidism was found in four families with missense variants, and enrichment of different tumor types was observed. In molecular studies, DNA-binding domain variants elicited differential expression of a small set of target genes relative to wild-type ZFX in cultured cells, suggesting a gain or loss of transcriptional activity. Additionally, a zebrafish model of ZFX loss displayed an altered behavioral phenotype, providing additional evidence for the functional significance of ZFX. Our clinical and experimental data support that variants in ZFX are associated with an X-linked intellectual disability syndrome characterized by a recurrent facial gestalt, neurocognitive and behavioral abnormalities, and an increased risk for congenital anomalies and hyperparathyroidism.


Assuntos
Hiperparatireoidismo , Deficiência Intelectual , Transtornos do Neurodesenvolvimento , Masculino , Feminino , Animais , Humanos , Deficiência Intelectual/patologia , Peixe-Zebra/genética , Mutação de Sentido Incorreto/genética , Fatores de Transcrição/genética , Fenótipo , Transtornos do Neurodesenvolvimento/genética
3.
Br J Cancer ; 128(11): 2013-2024, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37012319

RESUMO

BACKGROUND: Cisplatin (CDDP) is a mainstay treatment for advanced head and neck squamous cell carcinomas (HNSCC) despite a high frequency of innate and acquired resistance. We hypothesised that tumours acquire CDDP resistance through an enhanced reductive state dependent on metabolic rewiring. METHODS: To validate this model and understand how an adaptive metabolic programme might be imprinted, we performed an integrated analysis of CDDP-resistant HNSCC clones from multiple genomic backgrounds by whole-exome sequencing, RNA-seq, mass spectrometry, steady state and flux metabolomics. RESULTS: Inactivating KEAP1 mutations or reductions in KEAP1 RNA correlated with Nrf2 activation in CDDP-resistant cells, which functionally contributed to resistance. Proteomics identified elevation of downstream Nrf2 targets and the enrichment of enzymes involved in generation of biomass and reducing equivalents, metabolism of glucose, glutathione, NAD(P), and oxoacids. This was accompanied by biochemical and metabolic evidence of an enhanced reductive state dependent on coordinated glucose and glutamine catabolism, associated with reduced energy production and proliferation, despite normal mitochondrial structure and function. CONCLUSIONS: Our analysis identified coordinated metabolic changes associated with CDDP resistance that may provide new therapeutic avenues through targeting of these convergent pathways.


Assuntos
Antineoplásicos , Neoplasias de Cabeça e Pescoço , Humanos , Cisplatino/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Fator 2 Relacionado a NF-E2/genética , Resistencia a Medicamentos Antineoplásicos/genética , Linhagem Celular Tumoral , Glucose , Antineoplásicos/farmacologia
4.
Adv Radiat Oncol ; 7(6): 100989, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36420184

RESUMO

Purpose: An evolutionary action scoring algorithm (EAp53) based on phylogenetic sequence variations stratifies patients with head and neck squamous cell carcinoma (HNSCC) bearing TP53 missense mutations as high-risk, associated with poor outcomes, or low-risk, with similar outcomes as TP53 wild-type, and has been validated as a reliable prognostic marker. We performed this study to further validate prior findings demonstrating that EAp53 is a prognostic marker for patients with locally advanced HNSCC and explored its predictive value for treatment outcomes to adjuvant bio-chemoradiotherapy. Methods and Materials: Eighty-one resection samples from patients treated surgically for stage III or IV human papillomavirus-negative HNSCC with high-risk pathologic features, who received either radiation therapy + cetuximab + cisplatin (cisplatin) or radiation therapy + cetuximab + docetaxel (docetaxel) as adjuvant treatment in a phase 2 study were subjected to TP53 targeted sequencing and EAp53 scoring to correlate with clinical outcomes. Due to the limited sample size, patients were combined into 2 EAp53 groups: (1) wild-type or low-risk; and (2) high-risk or other. Results: At a median follow-up of 9.8 years, there was a significant interaction between EAp53 group and treatment for overall survival (P = .008), disease-free survival (P = .05), and distant metastasis (DM; P = .004). In wild-type or low-risk group, the docetaxel arm showed significantly better overall survival (hazard ratio [HR] 0.11, [0.03-0.36]), disease-free survival (HR 0.24, [0.09-0.61]), and less DM (HR 0.04, [0.01-0.31]) than the cisplatin arm. In high-risk or other group, differences between treatments were not statistically significant. Conclusions: The docetaxel arm was associated with better survival than the cisplatin arm for patients with wild-type or low-risk EAp53. These benefits appear to be largely driven by a reduction in DM.

5.
Nucleic Acids Res ; 50(12): e70, 2022 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-35412634

RESUMO

Discovering rare cancer driver genes is difficult because their mutational frequency is too low for statistical detection by computational methods. EPIMUTESTR is an integrative nearest-neighbor machine learning algorithm that identifies such marginal genes by modeling the fitness of their mutations with the phylogenetic Evolutionary Action (EA) score. Over cohorts of sequenced patients from The Cancer Genome Atlas representing 33 tumor types, EPIMUTESTR detected 214 previously inferred cancer driver genes and 137 new candidates never identified computationally before of which seven genes are supported in the COSMIC Cancer Gene Census. EPIMUTESTR achieved better robustness and specificity than existing methods in a number of benchmark methods and datasets.


Assuntos
Aprendizado de Máquina , Neoplasias , Humanos , Mutação , Neoplasias/genética , Neoplasias/patologia , Oncogenes , Filogenia
6.
Genome Res ; 32(5): 916-929, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35301263

RESUMO

Genetic variants drive the evolution of traits and diseases. We previously modeled these variants as small displacements in fitness landscapes and estimated their functional impact by differentiating the evolutionary relationship between genotype and phenotype. Conversely, here we integrate these derivatives to identify genes steering specific traits. Over cancer cohorts, integration identified 460 likely tumor-driving genes. Many have literature and experimental support but had eluded prior genomic searches for positive selection in tumors. Beyond providing cancer insights, these results introduce a general calculus of evolution to quantify the genotype-phenotype relationship and discover genes associated with complex traits and diseases.


Assuntos
Cálculos , Neoplasias , Evolução Biológica , Aptidão Genética , Genótipo , Humanos , Modelos Genéticos , Neoplasias/genética , Fenótipo , Seleção Genética
7.
Proc Natl Acad Sci U S A ; 118(51)2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34916293

RESUMO

G protein-coupled receptors (GPCRs) are the largest family of human proteins. They have a common structure and, signaling through a much smaller set of G proteins, arrestins, and effectors, activate downstream pathways that often modulate hallmark mechanisms of cancer. Because there are many more GPCRs than effectors, mutations in different receptors could perturb signaling similarly so as to favor a tumor. We hypothesized that somatic mutations in tumor samples may not be enriched within a single gene but rather that cognate mutations with similar effects on GPCR function are distributed across many receptors. To test this possibility, we systematically aggregated somatic cancer mutations across class A GPCRs and found a nonrandom distribution of positions with variant amino acid residues. Individual cancer types were enriched for highly impactful, recurrent mutations at selected cognate positions of known functional motifs. We also discovered that no single receptor drives this pattern, but rather multiple receptors contain amino acid substitutions at a few cognate positions. Phenotypic characterization suggests these mutations induce perturbation of G protein activation and/or ß-arrestin recruitment. These data suggest that recurrent impactful oncogenic mutations perturb different GPCRs to subvert signaling and promote tumor growth or survival. The possibility that multiple different GPCRs could moonlight as drivers or enablers of a given cancer through mutations located at cognate positions across GPCR paralogs opens a window into cancer mechanisms and potential approaches to therapeutics.


Assuntos
Regulação Neoplásica da Expressão Gênica/fisiologia , Neoplasias/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , beta-Arrestinas/metabolismo , Cálcio , Linhagem Celular Tumoral , Simulação por Computador , Ensaio de Imunoadsorção Enzimática , Humanos , Mutação , Neoplasias/genética , Conformação Proteica , Receptores Acoplados a Proteínas G/genética , beta-Arrestinas/genética
8.
Front Mol Biosci ; 8: 791792, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34966786

RESUMO

All tumors have DNA mutations, and a predictive understanding of those mutations could inform clinical treatments. However, 40% of the mutations are variants of unknown significance (VUS), with the challenge being to objectively predict whether a VUS is pathogenic and supports the tumor or whether it is benign. To objectively decode VUS, we mapped cancer sequence data and evolutionary trace (ET) scores onto crystallography and cryo-electron microscopy structures with variant impacts quantitated by evolutionary action (EA) measures. As tumors depend on helicases and nucleases to deal with transcription/replication stress, we targeted helicase-nuclease-RPA complexes: (1) XPB-XPD (within TFIIH), XPF-ERCC1, XPG, and RPA for transcription and nucleotide excision repair pathways and (2) BLM, EXO5, and RPA plus DNA2 for stalled replication fork restart. As validation, EA scoring predicts severe effects for most disease mutations, but disease mutants with low ET scores not only are likely destabilizing but also disrupt sophisticated allosteric mechanisms. For sites of disease mutations and VUS predicted to be severe, we found strong co-localization to ordered regions. Rare discrepancies highlighted the different survival requirements between disease and tumor mutations, as well as the value of examining proteins within complexes. In a genome-wide analysis of 33 cancer types, we found correlation between the number of mutations in each tumor and which pathways or functional processes in which the mutations occur, revealing different mutagenic routes to tumorigenesis. We also found upregulation of ancient genes including BLM, which supports a non-random and concerted cancer process: reversion to a unicellular, proliferation-uncontrolled, status by breaking multicellular constraints on cell division. Together, these genes and global analyses challenge the binary "driver" and "passenger" mutation paradigm, support a gradient impact as revealed by EA scoring from moderate to severe at a single gene level, and indicate reduced regulation as well as activity. The objective quantitative assessment of VUS scoring and gene overexpression in the context of functional interactions and pathways provides insights for biology, oncology, and precision medicine.

9.
Methods Enzymol ; 661: 407-431, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34776222

RESUMO

We present a Chemistry and Structure Screen Integrated Efficiently (CASSIE) approach (named for Greek prophet Cassandra) to design inhibitors for cancer biology and pathogenesis. CASSIE provides an effective path to target master keys to control the repair-replication interface for cancer cells and SARS CoV-2 pathogenesis as exemplified here by specific targeting of Poly(ADP-ribose) glycohydrolase (PARG) and ADP-ribose glycohydrolase ARH3 macrodomains plus SARS CoV-2 nonstructural protein 3 (Nsp3) Macrodomain 1 (Mac1) and Nsp15 nuclease. As opposed to the classical massive effort employing libraries with large numbers of compounds against single proteins, we make inhibitor design for multiple targets efficient. Our compact, chemically diverse, 5000 compound Goldilocks (GL) library has an intermediate number of compounds sized between fragments and drugs with predicted favorable ADME (absorption, distribution, metabolism, and excretion) and toxicological profiles. Amalgamating our core GL library with an approved drug (AD) library, we employ a combined GLAD library virtual screen, enabling an effective and efficient design cycle of ranked computer docking, top hit biophysical and cell validations, and defined bound structures using human proteins or their avatars. As new drug design is increasingly pathway directed as well as molecular and mechanism based, our CASSIE approach facilitates testing multiple related targets by efficiently turning a set of interacting drug discovery problems into a tractable medicinal chemistry engineering problem of optimizing affinity and ADME properties based upon early co-crystal structures. Optimization efforts are made efficient by a computationally-focused iterative chemistry and structure screen. Thus, we herein describe and apply CASSIE to define prototypic, specific inhibitors for PARG vs distinct inhibitors for the related macrodomains of ARH3 and SARS CoV-2 Nsp3 plus the SARS CoV-2 Nsp15 RNA nuclease.


Assuntos
COVID-19 , Ácidos Nucleicos , Síndrome Respiratória Aguda Grave , Reparo do DNA , Humanos , Simulação de Acoplamento Molecular , SARS-CoV-2
10.
Cancers (Basel) ; 13(16)2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34439147

RESUMO

BACKGROUND: PPARγ (peroxisome proliferator-activated receptor gamma) is involved in the pathology of numerous diseases, including UM and other types of cancer. Emerging evidence suggests that an interaction between PPARγ and DNMTs (DNA methyltransferase) plays a role in cancer that is yet to be defined. METHODS: The configuration of the repeating elements was performed with CAP3 and MAFFT, and the structural modelling was conducted with HDOCK. An evolutionary action scores algorithm was used to identify oncogenic variants. A systematic bioinformatic appraisal of PPARγ and DNMT1 was performed across 29 tumor types and UM available in The Cancer Genome Atlas (TCGA). RESULTS: PPAR-responsive elements (PPREs) enriched with Alu repeats are associated with different genomic regions, particularly the promotor region of DNMT1. PPARγ-DNMT1 co-expression is significantly associated with several cancers. C-terminals of PPARγ and DNMT1 appear to be the potential protein-protein interaction sites where disease-specific mutations may directly impair the respective protein functions. Furthermore, PPARγ expression could be identified as an additional prognostic marker for UM. CONCLUSIONS: We hypothesize that the function of PPARγ requires an additional contribution of Alu repeats which may directly influence the DNMT1 network. Regarding UM, PPARγ appears to be an additional discriminatory prognostic marker, in particular in disomy 3 tumors.

11.
Bioinformatics ; 37(17): 2675-2681, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34042953

RESUMO

MOTIVATION: Cancer dependencies provide potential drug targets. Unfortunately, dependencies differ among cancers and even individuals. To this end, visible neural networks (VNNs) are promising due to robust performance and the interpretability required for the biomedical field. RESULTS: We design Biological visible neural network (BioVNN) using pathway knowledge to predict cancer dependencies. Despite having fewer parameters, BioVNN marginally outperforms traditional neural networks (NNs) and converges faster. BioVNN also outperforms an NN based on randomized pathways. More importantly, dependency predictions can be explained by correlating with the neuron output states of relevant pathways, which suggest dependency mechanisms. In feature importance analysis, BioVNN recapitulates known reaction partners and proposes new ones. Such robust and interpretable VNNs may facilitate the understanding of cancer dependency and the development of targeted therapies. AVAILABILITY AND IMPLEMENTATION: Code and data are available at https://github.com/LichtargeLab/BioVNN. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

13.
Prog Biophys Mol Biol ; 163: 171-186, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33636189

RESUMO

Arrival of the novel SARS-CoV-2 has launched a worldwide effort to identify both pre-approved and novel therapeutics targeting the viral proteome, highlighting the urgent need for efficient drug discovery strategies. Even with effective vaccines, infection is possible, and at-risk populations would benefit from effective drug compounds that reduce the lethality and lasting damage of COVID-19 infection. The CoV-2 MacroD-like macrodomain (Mac1) is implicated in viral pathogenicity by disrupting host innate immunity through its mono (ADP-ribosyl) hydrolase activity, making it a prime target for antiviral therapy. We therefore solved the structure of CoV-2 Mac1 from non-structural protein 3 (Nsp3) and applied structural and sequence-based genetic tracing, including newly determined A. pompejana MacroD2 and GDAP2 amino acid sequences, to compare and contrast CoV-2 Mac1 with the functionally related human DNA-damage signaling factor poly (ADP-ribose) glycohydrolase (PARG). Previously, identified targetable features of the PARG active site allowed us to develop a pharmacologically useful PARG inhibitor (PARGi). Here, we developed a focused chemical library and determined 6 novel PARGi X-ray crystal structures for comparative analysis. We applied this knowledge to discovery of CoV-2 Mac1 inhibitors by combining computation and structural analysis to identify PARGi fragments with potential to bind the distal-ribose and adenosyl pockets of the CoV-2 Mac1 active site. Scaffold development of these PARGi fragments has yielded two novel compounds, PARG-345 and PARG-329, that crystallize within the Mac1 active site, providing critical structure-activity data and a pathway for inhibitor optimization. The reported structural findings demonstrate ways to harness our PARGi synthesis and characterization pipeline to develop CoV-2 Mac1 inhibitors targeting the ADP-ribose active site. Together, these structural and computational analyses reveal a path for accelerating development of antiviral therapeutics from pre-existing drug optimization pipelines.


Assuntos
Antivirais/química , Proteases Semelhantes à Papaína de Coronavírus/metabolismo , Inibidores Enzimáticos/química , Glicosídeo Hidrolases/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/química , Xantinas/química , Sequência de Aminoácidos , Antivirais/farmacologia , Domínio Catalítico , Cristalografia por Raios X , Descoberta de Drogas , Inibidores Enzimáticos/farmacologia , Humanos , Modelos Moleculares , Domínios Proteicos , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Relação Estrutura-Atividade , Xantinas/farmacologia , Tratamento Farmacológico da COVID-19
14.
Prog Biophys Mol Biol ; 163: 87-108, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33035590

RESUMO

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a key member of the phosphatidylinositol-3 kinase-like (PIKK) family of protein kinases with critical roles in DNA-double strand break repair, transcription, metastasis, mitosis, RNA processing, and innate and adaptive immunity. The absence of DNA-PKcs from many model organisms has led to the assumption that DNA-PKcs is a vertebrate-specific PIKK. Here, we find that DNA-PKcs is widely distributed in invertebrates, fungi, plants, and protists, and that threonines 2609, 2638, and 2647 of the ABCDE cluster of phosphorylation sites are highly conserved amongst most Eukaryotes. Furthermore, we identify highly conserved amino acid sequence motifs and domains that are characteristic of DNA-PKcs relative to other PIKKs. These include residues in the Forehead domain and a novel motif we have termed YRPD, located in an α helix C-terminal to the ABCDE phosphorylation site loop. Combining sequence with biochemistry plus structural data on human DNA-PKcs unveils conserved sequence and conformational features with functional insights and implications. The defined generally progressive DNA-PKcs sequence diversification uncovers conserved functionality supported by Evolutionary Trace analysis, suggesting that for many organisms both functional sites and evolutionary pressures remain identical due to fundamental cell biology. The mining of cancer genomic data and germline mutations causing human inherited disease reveal that robust DNA-PKcs activity in tumors is detrimental to patient survival, whereas germline mutations compromising function are linked to severe immunodeficiency and neuronal degeneration. We anticipate that these collective results will enable ongoing DNA-PKcs functional analyses with biological and medical implications.


Assuntos
Proteína Quinase Ativada por DNA , Proteínas de Ligação a DNA , DNA/metabolismo , Proteína Quinase Ativada por DNA/genética , Proteína Quinase Ativada por DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Humanos , Proteínas Nucleares/metabolismo , Fosforilação , Filogenia
15.
Cancers (Basel) ; 11(10)2019 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-31635116

RESUMO

The BAP1 (BRCA1-associated protein 1) gene is associated with a variety of human cancers. With its gene product being a nuclear ubiquitin carboxy-terminal hydrolase with deubiquitinase activity, BAP1 acts as a tumor suppressor gene with potential pleiotropic effects in multiple tumor types. Herein, we focused specifically on uveal melanoma (UM) in which BAP1 mutations are associated with a metastasizing phenotype and decreased survival rates. We identified the ubiquitin carboxyl hydrolase (UCH) domain as a major hotspot region for the pathogenic mutations with a high evolutionary action (EA) score. This also includes the mutations at conserved catalytic sites and the ones overlapping with the phosphorylation residues. Computational protein interaction studies revealed that distant BAP1-associated protein complexes (FOXK2, ASXL1, BARD1, BRCA1) could be directly impacted by this mutation paradigm. We also described the conformational transition related to BAP1-BRCA-BARD1 complex, which may pose critical implications for mutations, especially at the docking interfaces of these three proteins. The mutations affect - independent of being somatic or germline - the binding affinity of miRNAs embedded within the BAP1 locus, thereby altering the unique regulatory network. Apart from UM, BAP1 gene expression and survival associations were found to be predictive for the prognosis in several (n = 29) other cancer types. Herein, we suggest that although BAP1 is conceptually a driver gene in UM, it might contribute through its interaction partners and its regulatory miRNA network to various aspects of cancer. Taken together, these findings will pave the way to evaluate BAP1 in a variety of other human cancers with a shared mutational spectrum.

17.
Cell Rep ; 28(5): 1370-1384.e5, 2019 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-31365877

RESUMO

The TP53 tumor suppressor gene is frequently mutated in human cancers. An analysis of five data platforms in 10,225 patient samples from 32 cancers reported by The Cancer Genome Atlas (TCGA) enables comprehensive assessment of p53 pathway involvement in these cancers. More than 91% of TP53-mutant cancers exhibit second allele loss by mutation, chromosomal deletion, or copy-neutral loss of heterozygosity. TP53 mutations are associated with enhanced chromosomal instability, including increased amplification of oncogenes and deep deletion of tumor suppressor genes. Tumors with TP53 mutations differ from their non-mutated counterparts in RNA, miRNA, and protein expression patterns, with mutant TP53 tumors displaying enhanced expression of cell cycle progression genes and proteins. A mutant TP53 RNA expression signature shows significant correlation with reduced survival in 11 cancer types. Thus, TP53 mutation has profound effects on tumor cell genomic structure, expression, and clinical outlook.


Assuntos
Bases de Dados de Ácidos Nucleicos , Regulação Neoplásica da Expressão Gênica , Perda de Heterozigosidade , Neoplasias/genética , Proteína Supressora de Tumor p53/genética , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Proteína Supressora de Tumor p53/metabolismo
18.
Hum Mutat ; 40(9): 1530-1545, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31301157

RESUMO

Accurate prediction of the impact of genomic variation on phenotype is a major goal of computational biology and an important contributor to personalized medicine. Computational predictions can lead to a better understanding of the mechanisms underlying genetic diseases, including cancer, but their adoption requires thorough and unbiased assessment. Cystathionine-beta-synthase (CBS) is an enzyme that catalyzes the first step of the transsulfuration pathway, from homocysteine to cystathionine, and in which variations are associated with human hyperhomocysteinemia and homocystinuria. We have created a computational challenge under the CAGI framework to evaluate how well different methods can predict the phenotypic effect(s) of CBS single amino acid substitutions using a blinded experimental data set. CAGI participants were asked to predict yeast growth based on the identity of the mutations. The performance of the methods was evaluated using several metrics. The CBS challenge highlighted the difficulty of predicting the phenotype of an ex vivo system in a model organism when classification models were trained on human disease data. We also discuss the variations in difficulty of prediction for known benign and deleterious variants, as well as identify methodological and experimental constraints with lessons to be learned for future challenges.


Assuntos
Substituição de Aminoácidos , Biologia Computacional/métodos , Cistationina beta-Sintase/genética , Cistationina/metabolismo , Cistationina beta-Sintase/metabolismo , Homocisteína/metabolismo , Humanos , Fenótipo , Medicina de Precisão
19.
Hum Mutat ; 40(9): 1546-1556, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31294896

RESUMO

Testing for variation in BRCA1 and BRCA2 (commonly referred to as BRCA1/2), has emerged as a standard clinical practice and is helping countless women better understand and manage their heritable risk of breast and ovarian cancer. Yet the increased rate of BRCA1/2 testing has led to an increasing number of Variants of Uncertain Significance (VUS), and the rate of VUS discovery currently outpaces the rate of clinical variant interpretation. Computational prediction is a key component of the variant interpretation pipeline. In the CAGI5 ENIGMA Challenge, six prediction teams submitted predictions on 326 newly-interpreted variants from the ENIGMA Consortium. By evaluating these predictions against the new interpretations, we have gained a number of insights on the state of the art of variant prediction and specific steps to further advance this state of the art.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/diagnóstico , Biologia Computacional/métodos , Neoplasias Ovarianas/diagnóstico , Neoplasias da Mama/genética , Detecção Precoce de Câncer , Feminino , Predisposição Genética para Doença , Testes Genéticos , Variação Genética , Humanos , Modelos Genéticos , Neoplasias Ovarianas/genética
20.
Hum Mutat ; 40(9): 1612-1622, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31241222

RESUMO

The availability of disease-specific genomic data is critical for developing new computational methods that predict the pathogenicity of human variants and advance the field of precision medicine. However, the lack of gold standards to properly train and benchmark such methods is one of the greatest challenges in the field. In response to this challenge, the scientific community is invited to participate in the Critical Assessment for Genome Interpretation (CAGI), where unpublished disease variants are available for classification by in silico methods. As part of the CAGI-5 challenge, we evaluated the performance of 18 submissions and three additional methods in predicting the pathogenicity of single nucleotide variants (SNVs) in checkpoint kinase 2 (CHEK2) for cases of breast cancer in Hispanic females. As part of the assessment, the efficacy of the analysis method and the setup of the challenge were also considered. The results indicated that though the challenge could benefit from additional participant data, the combined generalized linear model analysis and odds of pathogenicity analysis provided a framework to evaluate the methods submitted for SNV pathogenicity identification and for comparison to other available methods. The outcome of this challenge and the approaches used can help guide further advancements in identifying SNV-disease relationships.


Assuntos
Neoplasias da Mama/genética , Quinase do Ponto de Checagem 2/genética , Biologia Computacional/métodos , Hispânico ou Latino/genética , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Neoplasias da Mama/etnologia , Estudos de Casos e Controles , Simulação por Computador , Feminino , Predisposição Genética para Doença , Humanos , Modelos Lineares , Pessoa de Meia-Idade , Estados Unidos/etnologia , Sequenciamento do Exoma
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